The elderly in general, and particularly patients who suffer from arthritis, are especially prone to a condition known as contracture. Contracture is the involuntary contraction of the muscles in the hand and wrist which cause the hand to rest in a closed, fist-like position, rather than in the slightly arched position of the normal relaxed hand. Contracture results from the shortening and thickening of the connective tissue which restricts the range of motion of the hand and wrist.
Contracture in an arthritic patient's hand may be corrected by the steady application of pressure having a tendency to force the patient's hand open and move it toward a normal relaxed position. Such pressure must be applied continuously over a period of time for the therapy to be successful. Additionally, the pressure must be periodically adjusted to account for movement of the patient's hand from the contracted position toward a normal position, so that the pressure is always tending to force the hand away from it's current position until a normal position is reached.
Prior art devices designed to correct contracture have suffered from many problems. A typical prior art device is illustrated in FIG. 1 and indicated generally at 100. The device 100 is shown in use by a patient and includes an air bladder 102 which may be inflated and deflated by means of valve 104. Air bladder 102 is coupled to wrist piece 106 which is secured to the patient's forearm by means of straps 108 and 110. Device 100 is used by inflating air bladder 102 with a first amount of air. This will cause air bladder 102 to apply pressure to the contracted hand, forcing the fingers away from the palm. After some period of time, the hand will adjust to this new position, and the air bladder 102 may then be further inflated with a second amount of air. This will cause air bladder 102 to apply further pressure to the hand, further forcing the fingers away from the palm. This procedure may be repeated as many times as necessary to slowly move the patient's fingers away from the palm.
An example of such prior art wrist splints to treat contracture is disclosed in U.S. Pat. No. 5,020,515 to Mann entitled "Inflatable Hand Splint". A similar device is disclosed in U.S. Pat. No. 5,056,504 also to Mann and also entitled "Inflatable Hand Splint". These prior art devices have the disadvantage that the fingers are moved away from the palm, but the hand is left in a semi-contracted position after treatment (i.e. the fingertips are still contracted). This is due to the fact that the distance the patient's fingers may be moved is limited by the thickness of air bladder 102 when fully inflated. Even a relatively large air bladder 102 will not be able to completely correct the contracture, because pressure is not applied to the patient's hand at the correct locations and in the correct directions to affect this. Furthermore, these prior art devices utilize a pliable wrist support element 106 which does not adequately support the patient's wrist during therapy. This pliable wrist support element is inadequate because it allows the patient's hand to bend at the wrist during therapy.
Consequently, there is a need for a device which will restore a patient's contracted hand to a normal, slightly arched, relaxed position while maintaining good support for the wrist. The present invention is directed toward meeting this need.